as required for the Born approximation [1]}, [2]}.
Next, the invariance of Eq. (REF ) under \(\Pi _{2}T\)  transformation
(REF ) leads to a symmetry relation for the Born amplitudes
\(f_{I_{3}^{\prime },I_{3}}\left(\vartheta ^{\prime }, \vartheta \right)= f_{I_{3},I_{3}^{\prime }}\left(\pi - \vartheta , \pi - \vartheta ^{\prime }\right).\) 
